1. Field of the Invention
This invention relates to automatic sand mold making apparatus and process, and more particularly to such apparatus and process which provide for precise reproduction of mold and core components for precision article casting.
2. Description of the Prior Art
Automatic sand mold and core making machines are available for foundry operations. One such line of machines is available from Redford Carver Foundry Supply Equipment, of Detroit, Mich. These machines are typically automated to form cores and mold components at room temperature by packing a mixture of mold sand and bonding material around a mold forming shape and by then driving a particular gas under pressure through the mold material mixture. The gas acts as a catalyst when it comes into contact with the bonding agent so that a solid sand mold component is produced. Further, an inert gas is passed under pressure through the formed sand mass to purge the catalytic gas from the sand mold component as well as from the interior of the machine prior to removing the formed mold components and cores therefrom. The pressures exerted by packing the sand around the mold forming pattern, passing the catalytic gas through the sand mass and purging the sand mass with inert gas produces a force against a plate (match plate) on which the mold pattern is mounted which may cause the plate to bend or deform in some other fashion. As a consequence, the resulting mold component will assume a shape which departs from that intended to be produced by the pattern. Moreover, if the mold component is a cope or a drag, the parting plane surface may not be flat on either the cope or the drag, whereby casting material poured into the cope and drag assembly may readily escape at the parting plane causing severe cast article cleanup problems (flashing formation) as well as dimensional aberrations in the end cast article.